QSDsan: Quantitative Sustainable Design for sanitation and resource recovery systems

This module is developed by:

Yalin Li <mailto.yalin.li@gmail.com>

This module is under the University of Illinois/NCSA Open Source License. Please refer to https://github.com/QSD-Group/QSDsan/blob/main/LICENSE.txt for license details.

class qsdsan.sanunits._excretion.Excretion(ID='', ins: Sequence[AbstractStream] | None = None, outs: Sequence[AbstractStream] | None = (), thermo=None, init_with='WasteStream', waste_ratio=0, **kwargs)

Estimation of N, P, K, and COD in urine and feces based on dietary intake for one person based on Trimmer et al.


waste_ratio (float) – A ratio in [0, 1] to indicate the amount of intake calories and nutrients (N, P, K) that is wasted.


bwaise systems


[1] Trimmer et al., Navigating Multidimensional Social–Ecological System Trade-Offs across Sanitation Alternatives in an Urban Informal Settlement. Environ. Sci. Technol. 2020, 54 (19), 12641–12653. https://doi.org/10.1021/acs.est.0c03296.

property Ca_fec

[float] Calcium excreted in feces, [g Ca/cap/d].

property Ca_ur

[float] Calcium excreted in urine, [g Ca/cap/d].

property K_cal

[float] Potassium intake relative to caloric intake, [g K/1000 kcal].

property K_exc

[float] Potassium excretion factor, [% of intake].

property K_ur

[float] Potassium recovered in urine, [wt%].

property Mg_fec

[float] Magnesium excreted in feces, [g Mg/cap/d].

property Mg_ur

[float] Magnesium excreted in urine, [g Mg/cap/d].

property N_exc

[float] Nitrogen excretion factor, [% of intake].

property N_fec_NH3

[float] Reduced inorganic nitrogen in feces, modeled as NH3, [% of total feces N].

property N_prot

[float] Nitrogen content in protein, [wt%].

property N_ur

[float] Nitrogen recovered in urine, [wt%].

property N_ur_NH3

[float] Reduced inorganic nitrogen in urine, modeled as NH3, [% of total urine N].

property P_exc

[float] Phosphorus excretion factor, [% of intake].

property P_prot_a

[float] Phosphorus content in animal protein, [wt%].

property P_prot_v

[float] Phosphorus content in vegetal protein, [wt%].

property P_ur

[float] Phosphorus recovered in urine, [wt%].

property e_cal

[float] Caloric intake, [kcal/cap/d].

property e_exc

[float] Energy excretion factor, [% of intake].

property e_fec

[float] Percent of excreted energy in feces, [%].

property fec_exc

[float] Feces generated per day, [g/cap/d].

property fec_moi

[float] Moisture (water) content of feces, [wt%].

line: str = 'Excretion'

class-attribute Name denoting the type of Unit class. Defaults to the class name of the first child class

property p_anim

[float] Animal protein intake, [g/cap/d].

property p_veg

[float] Vegetal protein intake, [g/cap/d].

property ur_exc

[float] Urine generated per day, [g/cap/d].

property ur_moi

[float] Moisture (water) content of urine, [wt%].

property waste_ratio

[float] The amount of intake calories and nutrients (N, P, K) that is wasted.


Not considered for Mg and Ca.